(3 of )Board of Supervisor administrative assistant Nicole Grebin, right and Chris Sorg, an employment and training counselor with the county volunteered their time to take phone calls from the public, Wednesday, Sept. 12, 2018, as five target locations using the federal Wireless Emergency Alerts system were tested. (KENT PORTER/ PD)

Sonoma County conducted a live trial run of its overhauled emergency alert system Wednesday, marking a closely-watched bid to see how well local governments can warn the public about disasters and other dangers nearly one year after the most destructive wildfire in state history.

Starting at 10 a.m., the county and Santa Rosa sent a series of test messages aimed at thousands of cellphones in five target locations using the federal Wireless Emergency Alerts system — the same program the county controversially opted not to use during last October’s wildfires, leaving many residents without any official warning.

The test was believed to be the first of its kind on the West Coast.

“Almost a year ago, we were smacked in the face by the most catastrophic wildfire in California’s history,” Sonoma County Board of Supervisors Chairman James Gore told reporters after the test. “We’ve been on our heels ever since, and this marks for us a day when we get back on our toes.”

The county failed to use the Amber Alert-style warnings during the firestorm last year because a previous emergency manager did not think the system could be sufficiently targeted to residents at risk. But a review from the state Office of Emergency Services released in February concluded that decision was “influenced by a limited awareness and understanding” of the system and “outdated information” about its technical capabilities.

Wednesday provided the county a public opportunity to test the implications of that finding.

The wireless messages were aimed first at cellphones in Guerneville, followed by Glen Ellen and Kenwood, then Healdsburg, Penngrove and finally Roseland. The tests concluded with countywide trial messages sent through local television and radio channels distributed through the federal Emergency Alert System.

Early reports indicated the cellphone messages were not always confined to the set boundaries planned by local administrators.

County officials noted “significant spillover” in some places, with messages intended for the Sonoma Valley received in Rohnert Park and Petaluma, according to Gore. The message targeted for Guerneville appeared to hit phones as far away as Graton and The Sea Ranch, he said.

And even in Guerneville, where flooding from the Russian River is common, many people received no message at all, said Supervisor Lynda Hopkins, who represents the region. Hopkins said she called the Russian River fire department and was told not a single employee there received a mobile notification.

Ensuring the success of wireless alerts in the Guerneville area is particularly important because of the large volume of tourists who drawn there, Hopkins said.

“If that system is not working in the lower Russian River, we need to work with our service providers to figure out what the gap is and how to address it,” she said. “A lot of people have my cellphone number. A lot of people know me on Facebook. And the fact that I am getting the vast majority of people saying that they did not actually receive a notification is very, very concerning to me.”

Some county officials personally experienced the “spillover” effect when, after the Roseland alert was sent, several people gathered at the emergency operations center in north Santa Rosa received alerts on their phones. All said they were AT&T customers.

Still, county leaders hailed Wednesday as a worthwhile and successful exercise because the technology worked and the public responded to the messages. And identifying the system’s weak spots was one of the reasons the test happened in the first place, county officials said.

Messages were sent in both English and Spanish. The English version read, “TEST message Sonoma County. www.socopsa.org to provide feedback. No other action needed.”

At the website, members of the public could fill out a survey to help officials learn how well the messages performed.

By about 12 p.m., after the tests had concluded, more than 1,300 surveys were filled out in English and 54 in Spanish. A few hours later, those numbers rose to about 2,500 and 150, respectively.

About 50 government staffers and first responders who were stationed among the five target areas were also set to provide feedback about the alerts.

One of the community members who filled out a survey was Jessica Tunis, a Santa Rosa resident whose mother, Linda, died when the Tubbs fire swept through the Journey’s End mobile home park last year. She believes her mother’s life could have been spared if the county had used Wireless Emergency Alerts in October.

Tunis worried the message she received Wednesday didn’t do enough to encourage more people to fill out a survey, but she was grateful the county tested the system.

“I’m glad they’re doing it. I hope other counties follow suit, because they need to learn how it works,” Tunis said. “It’s a learning curve, and they’re figuring out stuff they didn’t know, so I think everybody needs to do that.”

The tests came two days after the county did a separate trial run of its opt-in SoCo Alert system. Monday’s messages went to 290,000 phone numbers from people who enrolled in the warning system and a 911 database provided by AT&T and Frontier Communications. More than half of the calls reached a live person or answering machine, county officials said.

For Wednesday’s operation, the county chose Guerneville because of its propensity for flooding and its location in a mountainous, rural area. Glen Ellen and Kenwood were selected because of the wildfire risk in Sonoma Valley, where more than 400 homes were destroyed in the October fires. Healdsburg, meanwhile, was seen as an ideal spot to test alerts to an entire city where multiple emergencies — including fires and floods — could break out when a high number of tourists are also present.

In Penngrove, the county targeted a small, linear area to test the potential for sending messages there should a train accident or hazardous materials spill happen along the railway which bisects the community. Roseland was chosen by the county because of its location within city limits, its high population density and large number of Spanish speakers.

The wireless alerts could have reached an estimated 20,000 people based on the combined populations of the five targeted areas, but the real figure is likely far higher because of people passing through and the messages’ spread into other locations, according to the county. Officials said they weren’t able to say exactly how many people received the messages because cellphone companies don’t disclose the number of users their towers reach.

Santa Rosa police dispatchers sent the messages to Roseland, while Sonoma County emergency officials and the Sheriff’s Office sent the others. The messages were programmed in advance, since the tests required clearance from the federal government, a county spokeswoman said.

Santa Rosa Fire chief Tony Gossner said the city’s emergency leaders will use the results of Wednesday’s test to hone their alerting capabilities, but he also stressed the importance of residents signing up for opt-in systems like SoCo Alert and being vigilant themselves.

“This is a shared responsibility. We cannot alert you with every single piece of equipment if you do not participate,” Gossner said in remarks to reporters. “You have to be prepared for an emergency at your home and at your place of business.”

Those who were in the targeted areas during Wednesday’s tests, from 10 a.m. to 11 a.m., and who did not received a cellphone alert were asked to fill out the related online survey, available through socopsa.org.

An analysis of the test results is slated to be presented to county leaders, city leaders and local public safety chiefs in early October.

You can reach Staff Writer J.D. Morris at 707-521-5337 or jd.morris@pressdemocrat.com. On Twitter @thejdmorris.